Side wall core taking apparatus



April 16, 1963 J. D. BENNETT SIDE WALL CORE TAKING APPARATUS 2 Sheets-Sheet 1 Filed March 9, 1960 FIG. 4.

ATTORNEYS KEEHHEEH FIG.

April 16, 1963 J. D. BENNETT SIDE WALL CORE TAKING APPARATUS 2 Sheets-Sheet 2 Filed March 9, 1960 F I INVENTOR.

JOHN D. BENNETT ATTORNEYS tates This invention relates generally to well drilling apparatus, and more particularly to improvements in side wall coring devices. One of the objects of the present invention is to provide an improved side wall coring device which effectively serves as a section of the drill stem and remains in the drill stem during the drilling operation, while being controllable from the surface.

Another object is to provide a coring apparatus for the sequential taking of cores at diiferent positions. This is accomplished by the provision of a sheath embracing the drill stern and provided with openings through which the core takers may extend for selectively taking sequential samples, and by the provision of actuating means for stepping the sheath about the drill stem to thereby effect projection of the core takers through said openings in predetermined sequence for taking samples.

A further object is to provide such a device with control means actuated by producing drilling mud pressure differentials internally of the drill stem by starting and stopping the drilling mud pumping means. A device of the indicated type is disclosed in the co-pending application of John D. Bennett and Preston E. Chaney, Serial No. 856,427, filed December 1, 1959. An advantage of the apparatus in accordance with the present invention is that it is a more simple, compact and reliable structure permitting economy in manufacture and facilitating installation and repair.

Other objects of the invention will appear more fully from the following description read in conjunction with the accompanying drawings, in which:

'FIGURE 1 is a fragmentary external view of a portion of the side wall core taker in accordance with the invention;

FIGURE 2 is a fragmentary longitudinal section through a side wall coring device in accordance with the invention;

FIGURE 3 is a fragmentary longitudinal section similar to FIGURE 2, showing one of the core takers shortly after beginning its entry into the side wall of the well;

FIGURE 4 is an external view of the portion of the drill stem section in accordance with the present invention;

FIGURE 5 is a section taken on the plane indicated at 55 in FIGURE 3;

FIGURE 6 is a developed view looking at the sheath which embraces the core takers, the openings in the sheath and core takers being shown in non-registering relation, the condition that obtains when the device is lowered into the well; and

FIGURE 7 is an elevation of a slug adapted to be dropped into the drill stern for the control of coring operation.

A preferred embodiment in accordance with the invention comprises a tubular body 16 which is threadedly connected in the drill stem between a drill stem section 12, which would usually be the drill collar, and a section 14 at joints 16 and 18, respectively. As shown in FIG- URE 5, tubular body is grooved, as at 20, to provide for longitudinally extending circumferentially equally spaced formations 22. In each of the formations 22 there are formed four longitudinally spaced pockets 24. There are four tiers of such formations 22 and pockets 24 with each pocket 24 accommodating a core taker in the form 3,085,637 Patented Apr. 16, 1963 of a tube 26 mounted in a fitting 28 having a pin 30 extending therethrough and mounting torsion springs 32.

Wrapped around the lower end portion of tubular body 10 is a compression spring 34 which is embraced by a collar 36 for its protection against damage during drilling. Seated upon the collar 36 is the lower end portion of a cylindrical sheath 38 embracing body 10. The torsion springs 32 bias the core takers outwardly and upwardly, but normally they are secured against such movement by sheath 38.

Referring particularly to FIGURE 6, the sheath 38 is provided with four openings 40, respectively, for the four tiers of pockets 24 formed in the body 10. These openings 4! are arranged, as shown, so that they register with the pockets 24 and core takers 26 one at a time.

Means are provided for indexing or stepping the sheath 38 about body 10 to register successively with each of the pockets 24. This indexing means comprises a piston means in the form of a tubular member 42 positioned within tubular body 10 and slidable relative thereto. Tubular member 42 is connected to a cylindrical drive ratchet 44, which embraces the outer wall of tube 10 and is slidable relative thereto, by means of a plurality of cylindrical cam followers 46 projecting through openings 48 in tubular member 42. Openings 48 define cam tracks for guiding the movement of cam followers 46. Cam followers 46 are fixedly secured to tubular member 42 by screws 50 which are threaded through the cam followers 46 into threaded engagement with tubular member 42. Cam followers 46 extend through the openings 48 into openings 51 in drive ratchet 44 of substantially the same outer diameter as the cam followers 46 and are substantially flush with the outer wall of driveratchet 44. Although any number of cam followers 46 and openings 48 may be employed, two are used in the illustrated embodiment of the invention and would be preferable.

It will thus be apparent that the tubular member 42, the cam followers 46 land the drive ratchet 44 are conjointly movable as a unitary structure relative tothe tubular body 10. A spring 52 is mounted in compression between an annular shoulder 53 formed in the inner wall of tubular body 10 and a collar '54 contacting the lower end of tubular member 42. Compression spring 52 thus biases the assembly comprising tubular member 42 and sheath 38 upward to a home position determined by contact of the upper end of sheath 38 with a shoulder 55 formed in the outer wall of tubular body 10 as is best illustrated in FIGURE 2. Y

A pair of sealing rings 56 and 57 of a sealing material, such as neoprene, are provided for restricting the drilling mud from entering between the cooperating walls of tubular member 42 and tubular body 10 to prevent the erosion of these walls by the drilling mud. Sealing ring 56 is mounted in a groove 58 adjacent the upper end of tubular member 42 and sealing ring 56 is mounted in a groove 60 at the lower end of tubular member 42.

As is shown in FIGURE 4, cam track openings 43 extend helically relative to the drill stem axis and serve to guide the travel of the assembly comprising tubular member 42 and dnive ratchet 44 helically relative to the tubular body 10. Formed at the lowermost end of drive ratchet 44 are downwardly extending teeth 62 which mesh with upwardly extending teeth 64 formed at the upper end of sheath 38. It will be apparent that the downward helical movement of drive ratchet 44, which may be termed the power stroke, is limited by the contact of the cam followers 46 with the lowermost end of openings 48. Since the drive ratchet 44 and the sheath 38 are in engagement by reason of meshing teeth 62 and 64 'dur-, ing this power stroke, the sheath 38 will also be actuated through this downward helical movement.

In order to permit movement of the drive ratchet 44 relative to a sheath 38 on the return movement of the former from the lowermost position thereof to the home position, a latch means is provided which serves to disengage the sheath 42 from the drive ratchet 44. This latch means comprises a pair of elongated latching members 66 mounted in openings 68 in tubular body 10. batching members 66 are pivoted on centrally positioned pins 70. The lower ends of latching member 66 are biased outwardly by compression springs 72 urging a hollow pin 74 outwardly from a recess 76 in latching member 66 into contact with the tubular member 42. Upon movement of tubular member 42 and sheath 38 to the lowermost position thereof, each of the lower ends of latching members 66 is moved outwardly under the action of springs 72 into one of a plurality of slots 78 provided in sheath 38, sixteen of the slots 38 being provided to accommodate the sixteen core taking positions of the sheath 38. At the same time, the upper ends of latching members 66 move inwardly into an annular groove 80 provided with tubular member 42. The latching members 66 are constructed to fit snugly into the slots 78 to thereby restrict rotation of sheath 38 relative to tubular body 10. Latching members 66 also restrict any upward movement of sheath 38 since such movement would cause contact by the lower edges of slots 78 with the lower edges of latching member 66. On the return helical movement of the assembly comprising tubular member 42 and drive ratchet 44 from the lower position thereof to the home position, the latching member 66 will restrict the sheath 38 from such helical movement to disengage the same in a manner to be set forth more fully hereinafter in connection with the description of the operation of the apparatus.

Formed on the upper end of tubular member 42 is a landing shoulder 86 adapted for supporting a slug 88 comprising a spearhead 90 and a restricted longitudinal passage 92. Alternatively, as later described, a housing of a bore hole logging apparatus may be seated at shoulder 86.

The coring tool is connected in the drill stem and remains there during the drilling operation. As the drilling mud is pumped down through the internal bore in the drill stem during the drilling operation, the drive ratchet 44 and the sheath 38 are maintained in the home position by the action of springs 34 and 52. Initially, the sheath 38 is positioned so that none of the openings 40 registers with a core taker as is indicated in FIGURE 6. The sheath 38 holds the core takers in position in the lower end portions of the pockets 24 against the influence of the torsion springs 32. The drilling position of the coring device is shown in FIGURE 2.

Assuming, first, that logging is not involved and it is desired to core the side wall 94 of the well. The drill stem is raised a distance sufiicient to place the lowermost tier of core takers 26 at the level of the side wall area to be cored, land the slug 88 is dropped into the stem. The slug 88 comes to rest upon the shoulder 86. Generally, this would occur during interruption of the mud circulation. When circulation is resumed, a gradient in drilling mud pressure is caused by the resistance to the flow of mud due to the restricted passage 92 in slug 88. This pressure gradient in the drill stem drives the tubular member 42, the drive ratchet 44 and the sheath 38 downwardly against the bias of springs 34 and 52. As the cam followers 46 move in the helical cam tracks provided by openings 48, the drive ratchet 44 is advanced about tubular body 10. Since the teeth 62 and 64 are engaged, the sheath 38 turns with the drive ratchet 44 to a position in which one of the core takers in the lowermost tier thereof registers with the associated openings 40, whereupon the core taker is swung outwardly through the opening 40 under the bias of its torsion spring 32. The free end of the core taker engages the side Wall 94 of the well and is arrested thereby in a position extending outwardly and downwardly. This position of the coring device is shown in FIGURE 3. In the lower position of the sheath 38, two of the openings 78 are in registry with the pair' of latching members 66 whereby the latter move outwardly under the action of springs 72 to extend into such registering openings 78.

The drilling mud is then stopped, or its pumping rate is considerably reduced. This reduces the differential pressures on opposite sides of the slug 88 to permit return of the drive ratchet 44 to the home position by the action of spring 52. As the drive ratchet 44 begins its return helical movement toward the home position, the sheath 38 will be held in its lower position by the latching members 66 which prevent both upward and rotatative movement of the sheath 38 by reason of the snug fit of the latching members 66 in openings 78. Since the sheath 38 is held in its lower position there will be a minimum of interference between the teeth 62 and 64 tending to prevent the return rotation of the drive ratchet. The sheath 38 will adjust for this interference by being forced downwardly against the bias of spring 34 as a result of the mutual camming action of the teeth 62 and 64 as the drive ratchet 44 moves helically upwardly. While the core taker projecting out of the opening 49 would also serve to arrest rotation of the sheath 38, the latching members 66 relieve the core taker of this function whereby the core takers are not subjected to repeated stresses during the core taking operations.

After the drive ratchet 44 has moved upwardly a dis tance so that the teeth 62 and 64 are fully disengaged, the lower portion 82 of the groove 88 will contact the upper ends of latching members 66 and upon continued upward movement of the drive ratchet 44, portion 82 will cam latching members 66 into openings 68 whereby the sheath 38 is no longer restricted against upward movement. Spring 34 will thus urge sheath 38 upwardly into reengagement with drive ratchet 44. However, since the drive ratchet 44 has been rotated relative to the sheath 38, teeth 62 and 64 will reengage at a position wherein sheath 38 is advanced one tooth spacing with respect to its original position prior to the power stroke.

In order to take a sample, the drill stem is now lowered a short distance, in consequence of which the core taker is driven into the side wall 94 of the well, and swings outwardly and upwardly through a horizontal position and emerges from the side wall when it is in a position extending outwardly and upwardly. As soon as the core taker is free of the side wall, the torsion spring 32 flips the core taker further upwardly into the upper end portion of the pocket 24. The sheath 38 is thus simultaneously freed for rotation through a subsequent power stroke since the core taker will no longer interfere with such movement.

The drill stem is then raised to position the second i.e., next to the lowermost, tier of core takers at the level of the second side wall area to be cored. The core taking procedure outlined above, including reapplication of mud pressure by renewal of full flow, release of pressure, and downward drill stem movement is repeated, and this time a sample is taken by a core taker in the second tier of core takers and circumferentially spaced from the core taker that took the first sample, this second core taker being now in alignment with an opening 40. The drill stem is then raised again to position the third, i.e., next to the topmost, tier of core takers at the level of the third side wall area to be cored. The core taking procedure is repeated again, and this time a sample is taken by a core taker in the third tier of core takers and diametrically opposite the core taker that took the first sample. The drill stem is again raised to position the topmost tier of core takers at the level of the fourth side wall area to be cored. The core taking procedure is repeated once again, and this time a sample is taken by a core taker in the fourth tier of core takers and circumferentially spaced 270 from the core taker that took the first sample. Now the whole operation is repeated, starting with the second core taker in the first tier of core takers. In all, with the arrangement illustrated, sixteen core samples may be thus taken sequentially. It will be understood that each time the sheath 38 is advanced about the drill stem, an opening 40 is moved out of registry with an underlying pocket 24, whereupon the associated core taker and the sample just taken thereby are completely encased and protected from returning drilling mud, and another opening 40 is moved into registry with one of its associated pockets 26, whereupon another core taker is released for taking a sample.

It will be evident from the foregoing that successive cores are taken in predetermined sequence, so that by keeping a record of the levels at which the coring procedure is repeated, each core may be positively identified with the level at which it was taken.

Drilling may be resumed at any time by retrieving the slug to permit again the free flow of mud. This may be accomplished by lowering on a Wire line an overshot to engage the spearhead 90 so that upon withdrawal of the overshot the slug may be removed. If drilling is not to be resumed after taking cores, the slug 88 may, of course, be recovered on raising the drill stem to recover the cores and/or change the bit.

In connection with the use of this coring device it may be desirable to effect electrical or other logging. Suitable apparatus for electrical logging is disclosed in the application of Fred M. M-ayes and Jack Weir Jones, Serial No. 818,066, filed June 4, 1959, and in the application of John D. Bennett, Preston E. Chaney, Jack Weir Jones and Fred M. Mayes, Serial No. 818,162, filed June 4, 1959. As disclosed in these applications an apparatus comprising a housing and a flexible electrode assembly is lowered through the drill stem so that the flexible electrode assembly becomes projected through openings in a bit, the apparatus coming to rest with the housing on a seat. If logging is to be accomplished with the present apparatus, the housing may come to rest on the seat 86 and then take the place of the slug 88 in restricting the flow of mud, serving in the same fashion as the slug 88 to efiect coring operations.

While other procedures may be used for both logging and coring, a typical and advantageous procedure might well involve the following:

After the completion of a drilling operation in which a new length of the bore hole is produced, the drill stem may be lifted from the bottom and the logging apparatus introduced at its upper end and permitted to drop, or be lowered, so that the flexible electrode will enter and pass through an opening of a jet bit and extend downwardly below the bit, the housing reaching its lowermost position when it comes to res-t on the seat 86. At this time, the flexible electrode assembly would have its full length extended through the bit. The drill stem may then be raised, as described in said copending applications to eifect automatic logging of the desired portion of the bore hole which would usually be that portion last drilled.

Assuming that electrical logging of another earlier drilled portion of the hole had already been accomplished and the logging result had been analyzed, it might be desirable then to take cores at particular levels of special interest as exhibited by the log. For this purpose, then, the drill stem could be repositioned at successive levels to effect coring, during which operations the sequential core taking could be controlled by control of drilling mud pressure, the housing of the logging apparatus then functions in the same fashion as the slug 88 to restrict mud flow and provide differential pressure to effect stepping movements of the sheath 38. After completion of these successive logging and coring operations, the logging assembly could be removed by an overshot so that, if desired, drilling could be resumed. It will be noted that the coring apparatus contains a central passage which would not impede the projection of the electrode assembly.

It will be understood, of course, that the present invention is susceptible of various changes and modifications without departing from the general principles of the invention. For example, the number of core takers employed and the order in which the core takers operate may be varied. Accordingly, the invention is not to be regarded as limited except as required by the following claims.

What is claimed is:

1. A core taking device for drilled wells comprising a body adapted for connection in a drill stem, a plurality of core taker tubes pivotally connected to said body, means biasing said core tubes for vertical swinging movement thereof outwardly from said body for taking samples, tubular means enclosing said body for securing said core tubes against outward swinging movement, having an opening therein for registration with each core tube and movable through a path to successively register an opening with each core tube for releasing said core tube for swinging movement thereof outwardly for taking samples, means movably mounted on said body adapted to be movable in response to differential drilling mud pressures within the drill stem for actuating said tubular means through said movement thereof, means interconnecting said actuating means and said tubular means including a ratchet member carried by said actuating means and a catch member carried by said tubular means engageable with said ratchet member, and latching means mounted on said body for engagement with said tubular means for restricting movement thereof from each of said successive core tube releasing positions, said actuating means being contractable with said latching means to actuate the same to free said tubular means for movement from each of said successive positions.

2. A core taking device for drilled well-s comprising a tubular body adapted for connection in a drill stern, a plurality of core taker tubes pivotally connected to said body and continuously biased for vertical swinging movement thereof outwardly from said body for taking samples, sheath means mounted on the exterior of said tubular body for rotation with respect to said body securing said core takers against outward swinging movement, said sheath means being movable and having openings therein adapted to receive said core takers and arranged to release said core takers successively in predetermined order for swinging movement thereof outwardly for taking samples, means responsive to differential drilling mud pressures and reciprocable from a home position through a power stroke and a return stroke back to said home position to index said securing means, said indexing means including a first tubular member mounted for movement interiorly of said tubular body in response to said differential drilling mud pressures, a second tubular member embracing said tubular body and movable thereon, a cam follower means extending through said tubular body interconnecting said tubular members for conjoint movement thereof, said tubular body defining a cam track at the portion thereof through which said cam follower means extends for guiding said movement of said indexing means, and ratchet means carried by said second tubular member, and interlock means carried by said sheath means and engageable with said ratchet means for transmitting movement of said indexing means to said sheath means.

3. A device as claimed in claim 2 wherein said cam track defines a helical path relative to said tubular body whereby said sheath means is indexed rotatably about said tubular body.

4. A device as claimed in claim 2 including latching means cooperable with said securing means for restricting movement thereof from each of said successive positions to cause disengagement of said securing means from said indexing means during a portion of said return movement,

said indexing means contacting said latching means during a portion of said return movement, said indexing means contacting said latching means during said return movement for actuating the same to free said securing means for movement from each of said successive positions into reengagement with said indexing means, said indexing means moving relative to said sheath means during said disengagement thereof.

5. A device as claimed in claim 4 wherein said latching means comprises a latch member pivotally mounted in said tubular body and said sheath means has a plurality of slots therein, said latch member being biased to ex tend into said slots and cooperable with any of said slots to restrict axial movement of said sheath means in the direction of said return movement and rotation of said sheath means in either direction about said tubular body.

6. A core taking device for drilled wells comprising a tubular body adapted for connection in a drill stem, a plurality of core taker tubes pivotally connected to said body and continuously biased -for vertical swinging movement thereof outwardly from said body for taking samples, means mounted on said body adjacent said core takers for securing said core takers against outward swinging movement and movable to core taking positions to release said core takers successively in predetermined order for swinging thereof outwardly for taking samples, means mounted on said body adapted to be responsive to differential drilling mud pressures and movable from a home position through a power stroke to a second position and from said second position through a return stroke back to said home position to index said securing means through said movement thereof, said indexing means having a driving member movable therewith between said positions thereof, said securing means having an element arranged for engagement and movement by said driving member during movement of said indexing means through said power stroke, said element being secured to said securing means for conjoint movement to transmit the movement of said driving member to said securing means in response to movement of said indexing means through a power stroke, said driving member being movable out of engagement with said element during movement of said indexing means through said return stroke, a latching means mounted on said body, said latching means being movable between a latching position in which said latching means engages said securing means to hold the same in said core taking positions thereof and a releasing position out of engagement with said securing means, said indexing means having cam means mounted thereon and contactable with said latching means during a portion of said return stroke thereof for actuating said latching means to said releasing position thereof to free said securing means for movement from each of said core taking positions into reengagement with said indexing means, said indexing means moving relative to said securing means during disengagement thereof.

7. A device as claimed in claim 6 wherein said securing means comprises a sheath member embracing said tubular body and having a plurality of openings therein, a first group of said openings being adapted to receive said latching means upon movement thereof into one of said latching positions, a second group of said openings being arranged to receive said core takers upon movement thereof outwardly for taking samples, said latching means cooperating with said first openings to restrict axial movement of said sheath member in one direction relative to said tubular body and rotation of said sheath member relative to said tubular body.

8. A device as claimed in claim 6 wherein said indexing means includes a first tubular member movable within said tubular body in response to said differential drilling mud pressures, a second tubular member embracing said tubular body and movable thereon and means interconnecting said tubular members, said driving member being carried by said second tubular member.

References Cited in the file of this patent UNITED STATES PATENTS 2,326,405 Spencer Aug. 10, 1943 2,697,585 Chaney et al Dec. 21, 1954 2,870,989 Laval Jan. 27, 1959 

1. A CORE TAKING DEVICE FOR DRILLED WELLS COMPRISING A BODY ADAPTED FOR CONNECTION IN A DRILL STEM, A PLURALITY OF CORE TAKER TUBES PIVOTALLY CONNECTED TO SAID BODY, MEANS BIASING SAID CORE TUBES FOR VERTICAL SWINGING MOVEMENT THEREOF OUTWARDLY FROM SAID BODY FOR TAKING SAMPLES, TUBULAR MEANS ENCLOSING SAID BODY FOR SECURING SAID CORE TUBES AGAINST OUTWARD SWINGING MOVEMENT, HAVING AN OPENING THEREIN FOR REGISTRATION WITH EACH CORE TUBE AND MOVABLE THROUGH A PATH TO SUCCESSIVELY REGISTER AN OPENING WITH EACH CORE TUBE FOR RELEASING SAID CORE TUBE FOR SWINGING MOVEMENT THEREOF OUTWARDLY FOR TAKING SAMPLES, MEANS MOVABLY MOUNTED ON SAID BODY ADAPTED TO BE MOVABLE IN RESPONSE TO DIFFERENTIAL DRILLING MUD PRESSURES WITHIN THE DRILL STEM FOR ACTUATING SAID TUBULAR MEANS THROUGH SAID MOVEMENT THEREOF, MEANS INTERCONNECTING SAID ACTUATING MEANS AND SAID TUBULAR MEANS INCLUDING A RATCHET MEMBER CARRIED BY SAID ACTUATING MEANS AND A CATCH MEMBER CARRIED BY SAID TUBULAR MEANS ENGAGEABLE WITH SAID RATCHET MEMBER, AND LATCHING MEANS MOUNTED ON SAID BODY FOR ENGAGEMENT WITH SAID TUBULAR MEANS FOR RESTRICTING MOVEMENT THEREOF FROM EACH OF SAID SUCCESSIVE CORE TUBE RELEASING POSITIONS, SAID ACTUATING MEANS BEING CONTRACTABLE WITH SAID LATCHING MEANS TO ACTUATE THE SAME TO FREE SAID TUBULAR MEANS FOR MOVEMENT FROM EACH OF SAID SUCCESSIVE POSITIONS. 